I am getting the error "error: Invalid use of AppleFarmer::AppleFarmer. I do not know why I am getting this error since I am not trying to pass any input into my Constructor. Is it possible I have an issue with my .h file? What am i doing wrong to get this error?
I have three different files, and I may also be having an issue with linking the code together as I am doing #include for a .cpp file. I am not sure if my code works aside from this error, but I am stuck on this error.
appleFarmerMain.cpp
#include<iostream>
#include "appleFarmer.cpp"
int main(){
AppleFarmer m;
int harvest;
int demand;
m.AppleFarmer();
while(m.endOfMonth()==false){
cout<<"Enter a harvest amount:"<<endl;
cin>>harvest;
m.harvestApples(harvest);
cout<<"Enter a demand:"<<endl;
cin>>demand;
m.sellApples(demand);
cout<<"Apple Inventory: "<<m.getInventory()<<endl;
m.updateCurrentDay();
}
return 0;
}
appleFarmer.cpp
#include "appleFarmer.h"
#include "<iostream>
using namespace std;
AppleFarmer::AppleFarmer(){
for(int i=0;i<30;i++){
sales[i]=0;
harvest[i]=0;
}
}
bool AppleFarmer::sellApples(int demand){
if(demand<= inventory){
sales[currentDay]=demand;
inventory=inventory-demand;
}
else{
sales[currentDay]=0;
}
}
void AppleFarmer::harvestApples(int dayHarvest){
harvest[currentDay]= dayHarvest;
inventory=inventory+dayHarvest;
}
bool AppleFarmer::endOfMonth(){
if (currentDay=maxDays){
return true;
}
else{
return false;
}
}
int AppleFarmer::updateCurrentDay(){
currentDay=currentDay+1;
}
int AppleFarmer::getInventory(){
return inventory;
}
double AppleFarmer::calculateAverageHarvest(){
}
double calculateAverageSales(){
}
void AppleFarmer::printSales(){
}
void AppleFarmer::printHarvest(){
}
appleFarmer.h
#ifndef APPLEFARMER_H
#define APPLEFARMER_H
class AppleFarmer
{
public:
AppleFarmer();
bool sellApples(int);
void harvestApples(int);
bool endOfMonth();
int updateCurrentDay();
int getInventory();
double calculateAverageHarvest();
double calculateAverageSales();
void printSales();
void printHarvest();
private:
int sales[30];
int harvest[30];
int maxDays = 30;
int currentDay = 0;
int inventory = 0;
};
#endif
In C++ you don't call the constructor on an object. That happens at object creation time. The line
m.AppleFarmer();
isn't needed. The constructor is implicitly called here:
AppleFarmer m;
You need to include appleFarmer.h instead of appleFarmer.cpp because the header file (with .h extension) contains the declaration while the .cpp file contains the implementation.
Then you need also to delete m.AppleFarmer(); because the constructor is called during the declaration (AppleFarmer m text line).
Related
I am new to coding in C++ and I want to make a simple Pokemon game.
I created a class in a header file and I am defining the functions in a separate .cpp file.
I also have a main file where I will run my actual code.
So I am defining a std::string function in my functions file, and it says std is an undeclared identifier.
Here are each of my files:
Function Definition:
#include "fns.hpp"
int Pokemon::getHP() {
return hp;
}
int Pokemon::getAttack() {
return attack;
}
int Pokemon::getDefense() {
return defense;
}
int Pokemon::getSpecialAttack() {
return specialAttack;
}
int Pokemon::getSpecialDefense() {
return specialDefense;
}
int Pokemon::getSpeed() {
return speed;
}
std::string Pokemon::getAttack1() {
return attack1;
}
std::string Pokemon::getAttack2() {
return attack2;
}
std::string Pokemon::getAttack3() {
return attack3;
}
std::string Pokemon::getAttack4() {
return attack4;
}
Pokemon::Pokemon(int qhp,int qdefense,int qattack,int qspecialAttack,int qspecialDefense,int qspeed,std::string qattack1,std::string qattack2,std::string qattack3,std::string qattack4)
: hp(qhp),attack(qattack),defense(qdefense),specialAttack(qspecialAttack),specialDefense(qspecialDefense),speed(qspeed),attack1(qattack),attack2(qattack2),attack3(qattack3),attack4(qattack4) {}
Function Declaration:
class Pokemon {
int hp,attack,defense,specialAttack,specialDefense,speed;
std::string attack1,attack2,attack3,attack4;
public:
int getHP();
int getAttack();
int getDefense();
int getSpecialAttack();
int getSpecialDefense();
int getSpeed();
int getAttack1();
int getAttack2();
int getAttack3();
int getAttack4();
Pokemon(int qhp,int qdefense,int qattack,int qspecialAttack,int qspecialDefense,int qspeed,std::string qattack1,std::string qattack2,std::string qattack3,std::string qattack4);
};
Whenever I say std::string, it says it is an undeclared identifier.
Can someone please help me?
It is because you have not used the library for it.
use the below at the top of your header file
#include<string>
I am getting an error message saying the use of undeclared identifier 'IntQueue' in vscode and I cannot figure out what is wrong.
I have tried renaming the file but still does not work. I created a separate header file that has the class defined and I included the header file in the main cpp file that has all the constructors defined. But I cannot figure out a way to solve the issue.
//This is the IntQueue.h header file
#ifdef _IntQueue_
#define _IntQueue_
#include<iostream>
#include<fstream>
using namespace std;
class IntQueue {
int* numbers;
int size;
int front;
int back;
public:
IntQueue (unsigned int n);
IntQueue();
~IntQueue();
int getSize() {return size;}
int getFront() {return front;}
int getBack() {return back;}
void incSize();
void pop();
int frontNumber();
void push(int i);
void reverse();
};
#endif
//This is the IntQueue.cpp file (incomplete)
#include "IntQueue.h"
IntQueue::IntQueue (unsigned int n) {
size = n;
numbers = new int[size];
front = 0;
back = 0;
}
IntQueue::IntQueue() {
size = 100;
front = 0;
back = 0
numbers = new int [size];
}
You need to change
#ifdef _IntQueue_
To
#ifndef _IntQueue_
When your .cpp file #include's your .h file, _IntQueue_ has not been declared yet, so the #ifdef skips the entire content of the .h file, and so the compiler doesn't know anything about your IntQueue class.
I have a simple class which I cannot instantiate and I don't know why...
Please help me !
-------Test.cpp-------
#include<iostream>
using namespace std;
#include "meteo.h"
int main()
{
Meteo meteo;
}
-------meteo.h---------
#ifndef METEO_H
#define METEO_H
class Meteo
{
public:
Meteo();
int Get(int i);
private:
char *list[];
};
#endif
-------meteo.cpp--------
#include "meteo.h"
Meteo::Meteo()
{
list[]("Sec","Venteux","Humide");
}
int Meteo::Get(int i)
{
return list[i];
}
I get the error: "undefined reference to `Meteo::Meteo()'"
It seems that the problem is that the compiler issued an error when was compiling the constructor
Meteo::Meteo()
{
list[]("Sec","Venteux","Humide");
}
and did not generate the object module.
This record
list[]("Sec","Venteux","Humide");
is invalid.
Try to change the class definition like
class Meteo
{
public:
Meteo();
int Get(int i);
private:
const char *list[3];
};
and define the constructor like
Meteo::Meteo() : list { "Sec","Venteux","Humide" }
{
}
The other reason might be that you did not include object module meteo in the project.
Take into account that this member function
int Meteo::Get(int i)
{
return list[i];
}
is also wrong. The type of elements of the array is const char * not int.
I am working on implementing stack in C++ without STL libraries.
Here is my code for the Header file
// File: stack.h: header file
#ifndef STACK_H
#define STACK_H
class Stack {
int MaxStack;
int EmptyStack;
int top;
int* items;
public:
Stack(int); // Constructor
~Stack(); //Destructor
//Member Functions
void push(int);
char pop();
int empty();
int full();
};
#endif // STACK_H
And the Cpp file
// File: stack.cpp: stack functions
#include "stack.h"
using namespace std;
// Constructor with argument
Stack::Stack(int size) {
MaxStack = size;
EmptyStack = -1;
top = EmptyStack;
items = new int[MaxStack];
}
// Destructor
Stack::~Stack() { delete[] items; }
void Stack::push(int c) {
items[++top] = c;
}
char Stack::pop() {
return items[top--];
}
// Test for Full stack
int Stack::full() {
return top + 1 == MaxStack;
}
// Test for Empty stack
int Stack::empty() {
return top == EmptyStack;
}
Before making a main to test the class when I run this I get these two errors
!(http://postimg.org/image/pnjzd9axt/)
Any help on how to solve these two errors ?!
Thanks in advance
The error says that you don't have a main function.
The errors like:
Unresolved external symbol are the compiler way of saying: I want X function, I expect it to be declared but I can not find it in the compiled and linked modules
The main function is not defined.
Add the following to your source code: int main() { return 0; }
As indicated by Emil, the compiler cannot find the definition for the main function.
I am hoping someone can point me in the right direction to figure out why I am getting the following error:
$~/display/triangleDisplayable.cc:4: undefined reference to `Displayable::Displayable()'
I am trying to abstract a class Displayable and have a class triangleDisplayable that implements its methods. The two header files I have are "Displayable.h":
class Displayable {
public:
Displayable();
virtual int getSizeOfArrays() = 0;
void display(int size);
private:
virtual void init() = 0;
virtual int getSizeOfPointsArray() = 0;
virtual int getSizeOfNormalsArray() = 0;
};
and "triangleDisplayable.h"
#include "Displayable.h"
class triangleDisplayable : public Displayable
{
public:
triangleDisplayable();
int getSizeOfArrays();
private:
void init();
int getSizeOfPointsArray();
int getSizeOfNormalsArray();
};
And then I have "Displayable.cc"
#include <iostream>
#include "Displayable.h"
Displayable::Displayable() {
std::cout << "testing Displayable constructor" << std::endl;
}
void Displayable:display(int size) {
}
int main () {
return 0;
}
and "triangleDisplayable.cc"
#include <iostream>
#include "triangleDisplayable.h"
triangleDisplayable::triangleDisplayable() : Displayable() {
}
int triangleDisplayable::getSizeOfArrays() {
return 0;
}
void triangleDisplayable::init() {
}
int triangleDisplayable::getSizeOfPointsArray() {
return 0;
}
int triangleDisplayable::getSizeOfNormalsArray() {
return 0;
}
int main () {
return 0;
}
I have been trying to follow along with various tutorials to learn how to do abstraction in C++, but I have not really been able to find any helpful solutions to this. I believe that all of my #includes are correct, which I read is a common problem. The error message seems to indicate that the problem is the line
triangleDisplayable::triangleDisplayable() : Displayable() {
}
I have tried to compile without the : Displayable() but I get the same error. Is there perhaps a problem with my syntax in my header files?
No, the error is in tool invocation. You need to link the two source files together (e.g. g++ -o foo a.cc b.cc). And remove one of the main functions, as you can't have two different ones.